title: Ki-67 can be used for further classification of triple negative breast cancer into two subtypes with different response and prognosis.
abstract: BACKGROUND
  Triple negative breast cancer (TNBC) has a poorer survival, despite a higher response rate to neoadjuvant chemotherapy. The purpose of this study was to identify the predictive or prognostic value of Ki-67 among patients with TNBC treated with neoadjuvant chemotherapy, and the role of Ki-67 in further classification of TNBC.
  
  
  METHODS
  A total of 105 TNBC patients who received neoadjuvant docetaxel/doxorubicin chemotherapy were included in the present study. Pathologic complete response (pCR) rate, relapse-free survival (RFS), and overall survival (OS) were compared according to the level of Ki-67.
  
  
  RESULTS
  pCR was observed in 13.3% of patients. TNBC with high Ki-67 expression (≥ 10%) showed a higher pCR rate to neoadjuvant chemotherapy than TNBC with low Ki-67 expression. None of the low Ki-67 group achieved pCR (18.2% in the high Ki-67 group vs. 0.0% in the low Ki-67 group, P = 0.019). However, a high Ki-67 expression was significantly associated with poor RFS and OS in TNBC, despite a higher pCR rate (P = 0.005, P = 0.019, respectively). In multivariate analysis, high Ki-67 was an independent prognostic factor for RFS in TNBC (hazard ratio = 7.82, P = 0.002). The high Ki-67 group showed a similar pattern of recurrence with overall TNBC, whereas the low Ki-67 group demonstrated a relatively constant hazard rate for relapse.
  
  
  CONCLUSIONS
  TNBC with high Ki-67 was associated with a more aggressive clinical feature despite a higher pCR rate. High proliferation index Ki-67 can be used for further classification of TNBC into two subtypes with different responses and prognosis.
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehang-ro, Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Bhumsuk
authors.initials: B
authors.lastname: Keam
authors.forename: Seock-Ah
authors.initials: SA
authors.lastname: Im
authors.forename: Kyung-Hun
authors.initials: KH
authors.lastname: Lee
authors.forename: Sae-Won
authors.initials: SW
authors.lastname: Han
authors.forename: Do-Youn
authors.initials: DY
authors.lastname: Oh
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Se-Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Wonshik
authors.initials: W
authors.lastname: Han
authors.forename: Dong-Wan
authors.initials: DW
authors.lastname: Kim
authors.forename: Tae-You
authors.initials: TY
authors.lastname: Kim
authors.forename: In Ae
authors.initials: IA
authors.lastname: Park
authors.forename: Dong-Young
authors.initials: DY
authors.lastname: Noh
authors.forename: Dae Seog
authors.initials: DS
authors.lastname: Heo
authors.forename: Yung-Jue
authors.initials: YJ
authors.lastname: Bang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000145:classification* / Q000188:drug therapy / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D000077143:Docetaxel; D004317:Doxorubicin / Q000008:administration & dosage / Q000627:therapeutic use; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000172:deficiency; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000096:biosynthesis / Q000172:deficiency; D043823:Taxoids / Q000008:administration & dosage / Q000627:therapeutic use; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D000077143:Docetaxel; D004317:Doxorubicin; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D043823:Taxoids; D016159:Tumor Suppressor Protein p53; C508053:ERBB2 protein, human